The major objectives of the proposed research are to define in modern terms the immunopathologic mechanisms of cutaneous LE and to examine the relationship between the cutaneous and systemic aspects of lupus erythematosus. This will be done in the following manner: (1) By studying the clinical, immunologic and immunopathologic features in well defined patients groups. (2) By examining and comparing the cell-type and functional characteristics of the cells in chronic, subacute and acute LE skin lesions. (3) By extending previous observations on the nature and mechanism of formation of subepidermal immunoglobulin deposits in SLE patients and NZB/W mice. The proposed studies will utilize direct and indirect immunofluorescence techniques and histochemical staining procedures for the identification of cells in tissue sections and in suspension following extraction from skin lesions. The response of cells extracted from LE skin lesions to mitogens, common antigens and putative "autoantigens" will be examined by standard blastogenic responses and assays for lymphokine activity. Immunoglobulin secreting cells from LE skin lesions will be quantitated by a reverse hemolytic plaque assay before and after stimulation with pokeweed mitogen. The indirect immuno-fluorescence Crithidia luciliae anti-DNA test will be used to identify DNA antibody in serum samples, tissue eluates and cell culture supernates. Fluorescein conjugated anti-DNA antibody will be used to identify DNA at the dermal-epidermal junction in LE skin lesions and in uninvolved LE skin. Ethidium bromide, a fluorescent dye that binds to DNA, will also be used to identify subepidermal DNA. Autoradiographic techniques will be used to trace epidermal DNA in NZB/W mice and to assess the relationship between variation in rates of epidermal cell division and accumulation of subepidermal immunoglobulin deposits. These studies will provide insight into the relative roles of cellular versus humoral mechanisms in the pathogenesis of LE skin disease and may lead to a more rational approach to treatment.